1. Field of the Invention
The present invention relates to a connector device which connects a power output device and an electric load each other and the present invention also relates to a power detecting apparatus utilizing the same.
2. Description of the Related Art
Conventionally, a power confirming test has been widely performed as one part of quality control in a production process of a product which corresponds to an electric load such as a direct current (DC) lamp for a projector or the like, for example. The power confirming test is performed for judgment whether quality of the product is good or bad by supplying a prescribed power to the electric load on a trial basis and by confirming a state of power at the same time.
As one example of embodiment of the above described power confirming test, an explanation will be given concretely on the power confirming test which is performed for a DC lamp that is an electric load with reference to FIG. 4. As shown in the diagram a power detecting apparatus 101 to perform the power confirming test includes a power supply 111 and a power meter 112. These are connected to each other via a power line (Ballast +Line) and a ground line (Ballast −Line). Further, the power meter 112 includes a connector 112a for connecting with a measuring object. In addition, a connector 102a to receive DC power is included in the DC lamp 102 being the measuring object.
At this point, respective connectors (102a, 112a) have positive (+) terminal which is the terminal in the power line side and negative (−) terminal which is the terminal in the ground line side. When the connectors 102a and 112a are connected, the positive terminal is connected with the positive terminal and the negative terminal is connected with the negative terminal surely by a locating lug and locating recess alternatively formed on the connectors.
By this kind of structure, it becomes possible to judge whether quality of the DC lamp 102 is good or bad by supplying a power from the power supply 111 with connecting the connector 112a of the power detecting apparatus 101 to the connector 102a of the DC lamp 102 and by confirming a state of power at the time utilizing the power meter 112. To be more concrete, when detected result of the power meter 112 is extraordinary, i.e., the result is not within a normal range, for example, it is recognized that resistance value of the DC lamp is extraordinary, and as a result it is decided that the DC lamp 102 is not a good product. Conversely, when the detected result is normal, it is decided that the DC lamp 102 is a good product. As for the conventional technology, it is recommended to refer to JP-A-2006-011085 and the like.
In the electric load such as the DC lamp, a direction in which the power should be input has been defined. When power having an inverse direction is input, i.e., power having a direction from the negative terminal to the positive terminal, there may be a possibility that problem is caused such that the lamp is broken or the like. At this point it makes to prevent the input of power having the inverse direction to the DC lamp as much as possible by the configuration in which the positive terminal is connected with the positive terminal and the negative terminal is connected with the negative terminal in each connector as above described.
However, by any cause there is a possibility of a situation that the power having the inverse direction is output from the power detecting apparatus side, that is to say, the power is output from the negative terminal side of the above described connector 112a. One example of it is that there is a possibility that the connector 112a deteriorates because it is necessary that the connector 112a is repeated to connect and disconnect with the connector 102a of many DC lamps in the above described power detecting apparatus 101.
At that time when the connector 112a is disconnected at point P which is shown by dotted line in FIG. 4, for example, in order to exchange for new connector 112a to be connected to main body of the power meter for repairing, it is conceivable that the new connector 112a is connected in reversed manner by mistake. If so, the power is output from the negative terminal side of the connector 112a as a result.
When the power confirming test for the DC lamp is performed in such a case, there is a possibility that the DC lamp is broken as above described. Even if the DC lamp is not broken, there is still a possibility that the DC lamp which has been damaged is shipped as a product and it is also conceivable that defective goods occur often at a later time, the damage of it becomes extensive.